Braking systems, such as those found on many aircraft, include a plurality of rotors mounted on a wheel. These rotors extend between a plurality of stators mounted on a fixed portion of a brake torque tube. Together the rotors and stators may be referred to as a brake stack or disk stack. To slow the rotation of the wheel, an actuator is used to compress the disk stack and produce friction between the rotors and stators.
The rotors in the disk stack may be connected to the wheel using beam keys mounted on the wheel. A beam key or drive key supporting a plurality of rotors is disclosed, for example, in U.S. Pat. No. 3,958,833 to Stanton, the contents of which is hereby incorporated by reference.
Known beam keys generally include a tang at a first end that is received in an opening parallel to the axis of rotation of the wheel being braked and a second end that is connected to an outer portion of the wheel. The outer end may be connected to the wheel by a fastener such as a bolt that is perpendicular to the wheel's axis of rotation or by a fastener that is angled with respect to the wheel's axis of rotation. A spacer or foot may also be included between the beam key and the wheel when a bolt perpendicular to the wheel's axis of rotation is used.
The use of a fastener angled with respect to the wheel's axis of rotation advantageously allows for a shorter, and thus lighter weight, beam key to be employed. A benefit of a shorter key is increased clearance with the brake assembly. FIG. 9 schematically illustrates an example of a beam key 200 mounted on a wheel 202 and arranged to receive a fastener. In this example, wheel 202 includes a bore 204 near a rim 206, bore 204 having a centerline 203 angled with respect to the circumferential inner surface 205 of wheel 202. Beam key 200 includes a boss 208 projecting from a lower side 210 of the key, and a bore 212 extends through the key 200 and the boss 208. The bore 212 of the key is coaxially aligned with the bore 204 of the wheel so that a fastener such as a bolt (not shown) can be passed though the bores 204, 212 to secure the key to the wheel. However, it has been found that when this arrangement is used, the wheel is prone to fail in the bore 204 due to the excessive load from a bolt against the bore, in the direction of arrow 214, for example. Another shortcoming is the propensity for the bolt to lose preload. It would therefore be desirable to provide a beam key and a beam key and wheel configuration that allows for the use of a fastener angled with respect to the axis of rotation of a wheel while minimizing or eliminating the structural problems that can lead to wheel and/or fastener failure.